1. Field of the Invention
This invention relates to an apparatus for filling a liquid friction coupling with a viscous liquid, which apparatus comprises a metering pump and plug connector means for connection to the liquid friction coupling.
2. Description of the Prior Art
The operating characteristics of a liquid friction coupling can be selected for a given viscous liquid employed in the coupling by a control of the filling ratio of the coupling. But difficulties are involved in an accurate adjustment of the filling ratio of the housing of the coupling. These difficulties arising in the control of the filling ratio are due to the fact that manufacturing tolerances of the several components of the coupling may have the result that the volume of the interior space of the coupling differs from the specified volume. Said difference may amount to a multiple of the permissible variation of the filling ratio.
An apparatus of the kind described first hereinbefore is known from Published German Application 36 18 207. But when the liquid friction coupling is in operation that known apparatus can be used only to supply working liquid in small amounts to the liquid friction coupling which is to be tested. Because an overfilling may also occur, it should be possible also to drain liquid because the filling operation would otherwise be unduly complicated.